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No. 386: Environmental monitoring of the Nalunaq Gold Mine, South Greenland 2004-2019

Bach, L. 2020. Environmental monitoring at the Nalunaq Gold Mine, South Greenland, 2004-2020. Aarhus University, DCE – Danish Centre for Environment and Energy, 76 pp. Scientific Report No. 386. http://dce2.au.dk/pub/SR386.pdf

Summary

The Nalunaq gold mine is located in Kirkespir Valley, 40 km northeast of the town Nanortalik, at the southernmost tip of Greenland. The gold deposit at Nalunaq was discovered in 1992 and in 2004 the Nalunaq gold mine opened. The ore was broken and shipped first to Europe and later to Canada for processing. Rising oil prices and shipping costs made the economics progressively difficult and the mine closed with the last shipment of ore in March 2009. In medio 2009, the mine re-opened now with full production of doré[1] in Nalunaq. A processing chamber was constructed inside the mountain and involved the carbon-in-pulp technology, which included the use of carbon and cyanide. Due to the use of cyanide to extract gold from the ore, strict control with the outflow of cyanide from the mine to the Kirkespir Valley is performed. The mining company Angel Mining Gold A/S closed its gold production in the Nalunaq area in November 2013 after which the area was decommissioned with a clean-up and restoration period lasting until August 2014.

Associated to the mining activities, there were in particular two main environmental risks: I) The risk of spreading of released metals due to the crushing effects of the body rock, ore processing, stock piling, deposition of waste-rock and tailings and driving on the gravel road. The environmental risks were associated with discharge of waste water from the process and to spreading of metals as dust particles. II) The risk of discharge of cyanide in toxic concentrations to the environment during the mining period 2009-2013. The risks were associated with discharge of mining process waste water or accidental spills of cyanide, e.g. from traffic accidents or incorrect pumping of cyanide solutions. As a result of those risks, an environmental monitoring program was developed to discover and avoid unwanted impacts to the environment.

Environmental monitoring was conducted yearly at Nalunaq from 2004 to 2019 to monitor the environmental impact from mining during and after the mining operation. This report provides an overview of the monitoring results and major findings. The sampling programme included lichens, Arctic char, sculpins, seaweed and blue mussels, which serve as key monitoring species in terrestrial and marine environments, respectively, supplemented with fresh water samples. 

The terrestrial environment was impacted by a moderate pollution of the elements arsenic (As), cobalt (Co), chromium (Cr) and cupper (Cu) dispersed as a result of dust spreading by wind from crushing of ore, waste rock and ore stockpiles, but also as a result from driving on the gravel road. Recommendations were given to minimise the dust pollution. After the restructuring of the mine production in 2009, the pollution decreased. This was a result of the processing of ore, including crushing, being placed inside the mountain, and that stockpiles of ore and crushed waste rock were removed from the terrestrial environment. The dust dispersal was then primarily related to traffic on the gravel road. Upon decommissioning of the mine in 2013, the dust pollution decreased even further and in 2017, four years after mine closure, the levels of elements measured in lichens were at or close to background levels. Based on the observed dust pollution, it is recommended for new mining projects in the future that adequate environmental requirements are set to avoid such effects in the future.

In the freshwater system, only small impacts were documented in the Kirkespir River. The river was impacted by drainage from ore and waste rock, and from 2009-2013, by diluted waste water from the mine that potentially could contain cyanide residues and elevated levels of elements. While water samples taken at the waterfall station showed no elevated concentrations of elements, the Arctic char at the site appeared, however, to accumulate some elements and in particularly Cadmium (Cd) was found at consistently slightly elevated concentrations. It was assessed that the slightly elevated concentrations cause no harm to the fish or the freshwater system. Four years after mining, in 2017, all measured concentrations in the livers of Arctic char were found to be at the same level as background concentrations. Concerning cyanide, no water samples collected in Kirkespir River have had cyanide concentrations above instrument detection limits. Cyanide is and has not at any time been considered to pose any risk to the biota including the Arctic char or to the environment.

The marine environment was monitored by analysing mussels, seaweed and livers from sculpin fish. While mussels showed no elevated element concentrations, sculpin livers and in particular seaweed samples had slightly elevated or elevated element concentrations. In particular, Cu concentrations were found to be elevated in seaweed. As it primarily was the stations around the Kirkespir River mouth that were impacted, it is assessed that the marine impact was related to accumulation of elements from the mine processing water brought to the marine environment through the river. Four years after closure, in 2017, the element concentrations in seaweed were still slightly elevated, but the concentrations are assessed to pose no risk to the biota and it is likely that the concentrations will decrease further with time.

The aerial mapping performed in 2019 identified old driving tracks in the terrain as well as various waste elements of different origins. In general, relatively few pieces of waste/scrap was localised in the terrain and it is assessed that the waste/scrap does not pose any risk to the environment, but that the impact is related solely to esthetical matters.

Overall, DCE assesses that the current environmental impact from the former mining activities to the environment at Nalunaq is insignificant and that no further actions are needed to reduce the environmental impact. The EIAs developed before the mining was initiated proved to be adequate in the way that they identified the potential impacts of the mining project. The EIA and supporting environmental studies made it possible to set environmental requirements in the license and design, and implement a suitable and detailed monitoring program. Environmental monitoring is considered to be completed with the environmental studies in 2019. Consequently, DCE considers the Nalunaq gold mine to serve as an example of how adequate environmental requirements, together with detailed environmental monitoring and regulation, can result in a mine operation in Greenland with limited environmental impact.



[1] A doré bar is a semi-pure alloy of gold and silver. It is usually created at the site of a mine and then transported to a refinery for further purification.